Calcium-sodium soap greases from highly oxidized waxes



Patented May 5, 1953 UNITED STATES ATENT GFFECE.

CALCIUM-SODIUM SOAP GREASES FROM HIGHLY OXIDIZED WAXES poration of Delaware Application April 2, 1951,

No Drawing.

Serial No. 218,904

9 Claims.

This invention relates to improved lubricating grease compositions and more particularly to lubricating greases containing mixed calcium and sodium soaps of oxidized paraiiin wax.

Oxidized petroleum fractions, including oxidized Waxes, have been employed heretofore as the source of saponifiable material in the production of lubricating greases. The oxidates employed for this purpose have been obtained by oxidizing selected petroleum fractions under controlled conditions such that the oxidation proceeds only to a fairly limited extent, for example to yield a product having an acid number of below about 100. Except for certain special purposes, oxidates obtained by carrying out the oxidation to a greater extent than this have been considered unsuitable for use in grease making.

According to the methods most commonly employed for utilizing these oxidation products, the saponifiable material which they contain, comprising acids and esters, is separated from the unsaponifiable material by solvent extraction, sweating or similar method. In order to avoid the expense of such a separation process, it has also been proposed to employ the entire oxidation product containing the unsaponifiable portions for the production of greases. However, the greases which have been produced by this method have a tendency to separate and to harden or set up in storage, in addition to other disadvantages due to the large proportion of wax-like unsaponifiable matter which they contain. They are characterized particularly by objectionably high low temperature torques and other undesirable low temperature properties. In general, it can be said that it has not been possible up to the present time to produce a grease from an oxidized petroleum fraction as the saponifiable material having equivalent properties to greases produced from the more expensive highly refined natural fats such as Snodotte acid, hydrogenated castor oil and triple pressed stearicacid.

The principal object of this invention is to provide a lubricating grease having improved lubricating properties over a wide temperature range. provide a wide temperature range lubricating grease having good water resistance and satis: factory storage characteristics. A further object is to provide a premium multi-duty lubricating Another object of this invention is to' grease based on relatively inexpensive and readily obtainable materials. A still further object of the invention is to provide an improved lubricating grease for automotive chassis lubrication employing a highly oxidized Wax as the source of saponifiable material. These and other objects will be apparent from the following disclosures.

In accordance with our invention, a grease satisfying the above objects is made by combining with a mineral oil fraction of lubricating characteristics a thickening agent comprising essentially a mixed calcium-sodium base soap prepared from a highly oxidized fraction of petroleum wax as the source of saponifiable material. Suitable oxidized wax fractions for forming these soaps have neutralization numbers in the range of from about 100 to about 300 and saponification numbers of from about 175 to about 450. They are preferably essentially acidlike rather than ester-like in character, so that the ratio of neutralization number to saponification number of such oxidized products is at least about 0.5. The crude oxidates may be saponified directly to form the mixed calcium-sodium base soaps for use in grease production according to our invention, or they may be subjected to a preliminary treatment such as water washing or acid treating for separation of undesirable fractions. Preferably, from a cost viewpoint, they are employed Without separation of unsaponifiable matter.

We have found that greases produced from mixed calcium-sodium base soaps of these high 1y oxidized waxes have exceptional lubricating properties over a wide temperature range, as well as satisfactory storage characteristics. The improved properties of these greases are based primarily upon the fact that they combine in a single grease higher dropping points (about 500+ *F.) than can be obtained from an equivalent soap content of the conventional sodium soap greases of natural fats, and essentially equivalent water resistance to the straight calcium soap water-stabilized greases which have dropping points of only about 210 F. In addition, they have a smooth texture, good shear resistance upon working, good high and low temperature properties, and show low leakage from bearings. They have the further advantage of ease and convenience in manufacture and reduced cost as compared with other greases of comparable quality.

Oxidates suitable for producing greases according to our invention are produced by oxidizing a petroleum wax such as crude or refined Wax, slack Wax or petrolatum at elevated temperatures, by means of an oxidizin agent, such as air or oxygen, until a high degree of oxidation is obtained indicated by a neutralization number of about 100 or more. The oxidation. is preferably carried out by passing air through the charge under superatmospheric pressure and in the presence of a catalyst. The process may be carried out at temperatures in the range of from about 200 F. to about 460 preferably in the range of from about 230 l. to about 330 F. and under pressures ranging from slightly abovejatmospheric. up to about 300 p. s. i. or more. Airrratesrare preferably sufdcient to provide adequate mixing of. the charge during the reaction without the use of other mechanical mixing means. They may be suitably within the range of about to about,

60 cubic feet per hour per pound of charge. The oxidation is continued for a sufficient period of time to obtain the desired degree of oxidation, which is usually a matter oi several hours under the fer-red conditions of operation.

ihe highly oxidized products thus obtained: difer markedly from the less highly oxidized products ordinarily employed in grease making, not only in the amount but also, in the; type of oxygenated compounds present. During the earlier stages of the oxidation of a hydrocarbon fraction the saponifiable material. formed comprises substantially only simple carboxyacids and their esters. Beyond a certain point, however, the oxidation of the originally produced oxygenates occurs at an accelerated rate, so thatcompounds of very diil erent characteristics are; produced due to the number and variety of oxygen. groups which they contain. It is found, for example, that the acids present in the highly oxidized products occur largely as hydroxyacids rather than straight carboxy acids as the case of the less highly oxidized products. fiable material also undergoes a changev due to oxygen absorption and decomposition reactions, so that it becomes less Wax-like in nature.-

Soaps of the desired type according to our invention are prepared from the highly oxidized materials by any of the, conventional methods employed for obtaining mixedbasesoaps,v such as by partial double decomposition. of. the sodium soap, by coprecipitation or by mixing separately prepared sodium and calciumsoaps- They are most conveniently prepared by the coprecipitation method, that is, by saponification or" theoxidate with calcium and sodium hydroxides or other suitable compounds to produce directly a mixed soap of the desired ratio. of calcium andsodium soaps.

The proportion of calcium in these mixedbase waxate soaps may range from a very small proportion up to about 60 per cent by weight of the total soap, depending upon the type of grease'to be produced. Preferably, the calcium soap com-- prises at least per cent of the total soap. In general, an approximately equal chemical proportion of calcium to sodium, or a ratio withinthe range of from about :60 to about :40, is preferred. Greases prepared from such. soaps combine the high droppin pointv and stability characteristics of the sodium soap greases with the high Water resistance of the calcium soap greases. This is in striking contrast. to the EX."

The unsaponiperience in producing mixed sodium-calcium soap greases from other types of saponifiable materials such as have been used heretofore, wherein only very limited amounts of calcium can be employed Without adversely affecting the dropping point and stability of the greases. U. S. 2,058,236, for example, teaches that in the production of ball and roller bearing greases employing stearic acid as the saponifiable material, the ratio of calcium to sodium should. be Within the limits 1:4 to 1:6.

A considerable excess of sodium or calcium hydroxide or of both sodium and calcium hydroxides beyond the theoretical amounts required to react with-thesaponifiable matter may be employed in forming these oxidate soaps. In the preparation of greases containing excess calcium hydroxide, sodium hydroxide is first added equivalentto from 40 to per cent, and preferably from. 4.0 to 60 per cent, of the saponifiabie matter in the oxidate material, and calcium hydroxide equivalent to up to per cent of the sapon'ifiable matter is then added. In the preparation of greases containing excess sodium hydroxide, the theoretical amounts of calcium and sodium. hydroxides are added, followed by additional amounts of sodium hydroxide sufilcientto give the desired excess. Preferably an excessof calcium or sodium hydroxide. is added equivalent to about 10 per cent of the alkali. required-for saponification of the. saponifiable material.

The proportions of soap to lubricating: oil may vary within wide limits to produce greases for various purposes ranging from semi-fluid to very stiff. For greases of the type ordinarily employed as chassis lubricants, for, example, the soap. contentv is suitably in the. range from about. 10 per centto about 30'per cent, andprei'erably from 15 per cent to, 30 per. centby WEl ht of the grease; and'for greasessuitable for use as. Wheel bearing lubricantsv the soap content may be up to 40 per cent or even higher, based on the weight of. the finished grease.

In addition to these special. soaps, the greases embodying our. invention, may contain, of the usual type additives such as, for example, oxidation. and corrosion inhibitors, extreme pressurev agents, oiliness agents and. so forth, as well as, small amounts of additional. thickening agents. such as polymeric: materials and solid lubricants. such as. carbonblack. These greases may also lie-mixed. or blended with. greases of other types if desired to produce greases. of special, properties.

The base. oils usedv in compoundin: these greases are lubricating oillfractions from paraffinic, naphthenic or mixed base crudcs. They. may be. obtained by any of, the usual refining methods such as acid. treating, solvent extrac-- tion or soforth. Suitable oil fractions may range from. fairly low to fairly high. viscosity, such as between about 30 seconds and 200 seconds Saybolt Universal at, 210 They are preferably in the range from about 3.0 secsndsto about seconds Saybolt. Universal viscosity. at 3l0 F.

Blends of residual and distillate oils are particularly suitable. for certain. applications.

The grease. preparation is suitably carried out by charging, av quantity of oxidate together with lime and caustic soda in. proportionate amounts to a. conventional grease making kettle, where themixture ismaintained at elevated temperature with stirring, air blowing or other mechanical agitation until thesaponification iscomplete, and. thenadding a quantity of lubricating. oil to the mass sufficient to produce a grease of the desired consistency. A small amount of the lubricating oil is preferably added to the initial charge also, with the addition of further amounts as the saponification progresses in order to maintain the plasticity of the mass. Other saponifiable materials such as the natural fats and oils commonly employed in grease making may also be added to the charge where it is desired to obtain a mixed grease.

The superior properties of the grease embodying our invention have been demonstrated in the preparation and testing of a large number of greases suitable for various purposes which were made from highly oxidized waxes of various types and from various types of mineral oil bases. The following examples illustrate the preparation and properties of these greases, and also show the effects of variables such as different types of oxidate treatments and the calcium-sodium ratio of the soap.

The oxidates employed in these examples were obtained by the method of air oxidation of the wax fraction at elevated temperatures and pressures and in the presence of a manganese catalyst.

The greases in the following examples were prepared by the method comprising introducing the oxidate and about one-fourth of the total amount of mineral oil employed as the oil base into a steam heated kettle and adding lime and caustic soda together with a small amount of water, the total amount of alkalies added being at least equal to the theoretical amount required to saponify all of the saponifiable material as calculated from the saponification number of the latter. The mixture thus obtained was heated with stirring for a sufiicient period of time to accomplish the saponificati-on and for an additional period of time to obtain the desired degree of dehydration. The remainder of the mineral oil was then added gradually and the grease allowed to 0001 to room temperature with continued stirring. The oxidation inhibitor or other additive was added during the cooling The oxidate was obtained by oxidizing a refined parafiin wax at a temperature of 270 F., a pressure of 65 p. s. i. g. and an air rate of cubic feet per hour per pound of charge. The oxidation was continued until the material being treated had a neutralization number of 192.

ber of 293 and contained 20.6 per cent of unsaponifiable material.

The mineral oil was a paraffinic lubricating oil fraction having an API gravity of 32.0 and a Saybolt Universal viscosity at 210 F. of 43.7.

The amounts of lime and caustic employed were thetheoretical amounts as calculated from the saponification number to give a 50:50 calciumzsodium soap, with no excess of alkali.

A tan, buttery grease was obtained having the following calculated composition:

The oxidate thus obtained had a saponification num- I Per cent Total soap, calculated 20.3 Water, ASTM 0.2 Free fatty acid, AS'I'M Neutral Mineral oil 1 77.6

Phenylalphanaphthylamine 1.9

flncludes 4.6 per cent unsaponifiable matter from wax oxidate.

EXAMPLE 2 A grease was prepared from the following ingredients:

Pounds Wax oxidate -1 10.00

Lime 1.59

Caustic (dry basis) 1.06 Mineral oil 21.6 Phenylalphanaphthylamine 0.48 Water (as aid in saponification) 4.0

The oxidate was obtained by the oxidation of a crude scale wax containing about 3 per cent of oil under the same conditions as described in Example 1. The oxidate obtained had a neutralization number of and a saponification number of 295, and contained 19 per cent of unsaponifiable material.

The mineral oil was of the same type as that employed in Example 1.

The amount of alkalies added was the theoretical amount to give a soap having a calciumsodium ratio of 50:50, with a 30 per cent excess of lime.

A grease of smooth buttery texture was obtained having the following composition:

Per cent Total soap, calculated 28.5 Water, ASTM 0.2 Mineral oil 69.9 Phenylalphanaphthylamine 1.4

1 Includes 5.7 per cent unsaponifiable matter from wax oxidate.

EXAMPLE 3 A grease was prepared from the following inradients:

gredients as in Example 1, except that the lime and caustic were added in proportions such as to give a soap having a calciumzsodium ratio of 25:75, and the phenylalphanaphthylamine was omitted.

A grease of smooth buttery texture was obtained having the following composition:

Per cent Total soap, calculated 20.8

Water, ASTM 0.2

Mineral oil 79.0

-Includes 4.7 per cent unsaponifiable matter from Wax oxidate.

A grease was prepared from the following inf gredients:

Pounds Wax oxidate 20.0- Lime 1.64. Caustic (dry basis) 1.7a Mineral oil 65.8 Water (as aid in saponification) 6.0 Phenylalphanaphthylamine 1.65

assassin Theoxidate was the same as that employed in Example 2, except thati't was subjected to an acid treatment. with dilute sulturic acid before use. The acid treatment was carried out at 150 51, using 3680 grams of duper cent sulfuric acid per 100 lbs. of oxidate. After the treatment, the oxidate was washed with water until free of mineral acid. The acid treated oxidate had a neutralization number of 157 and a saponification number of 244 and contained 21.6 per cent of unsaponifiable material.

The mineral oil was the same type as that employed in Example 1.

The amount of alkalies added was the theoreticalamount to give a soap having a calciumsodium ratio of 50:50. 7

A grease of smooth buttery texture was obtained having the following composition:

Per cent Total soap, calculated 20.6 r

and did not harden to an objectionable degree upon storage. Table 1. below shows test indicative of service characteristics for these greases incomparison with a commercial pr mium grade grease (A) employed as a wide emperature range ball and roller bearing lubricant.

TABLE I torque mounted on the top. The bearing packed with a 60 capacity charge of the grease to be tested is clamped at the inner race to the spindle, While the outer race is clamped immovably to a stationary cup within which the bearing is inserted. The assembly is inserted with the lower bearing end in a low temperature bath containing isopropyl alcohol, and the desired temperature of the bath and bearing is attained by dropping Dry Ice in the bath. The drum and drum extension carried at the upper end of the hollow spindle and protruding from the bath are held in vertical position by. a tapered roller bearing. The line coiled around the drum extends over a pulley to a container into which. the desired weights are added to apply the torque load. to the hollow spindle to thereby cause rotation of the spindle and inner race of the bearing with respect to the fixed outer race.v A time of. not less than two hours is utilized to cool the bearing to the test temperature, and an additional soaking period at the test temperature is permitted such. that the test is not rununtil three hours from the start of cooling. When the desired bearing temperature and soaking period are attained, a 2000 gram-centimeter torque load is applied in both clockwise and c'ou'nter-clockwise directions, and the number of seconds for one rotation is observed and the readings averaged.

The Dynamic Water Resistance testis that described in Arm-yNavy Aeronautical Specification AN-G-25, Low Temperature Aircraft Lubricating Grease; Item. F-4 October 9, 1947. This measures the resistance of the grease against Wide temperature range ball and roller bearing greases Grease N0 l. l I 2 Treatment CazNa Ratio Phen. V alphanaphthylaminc, Percent Oil Base:

Type Parafllnic. I

Viscosity, SUS, 210 F. 431...... Pen'ctraiion et 7-7 F., AST

Unworkedun 327 Worked 60 Strokes 342 Per Norma niofimann Oxidation at 210 F.:

.00. i's. ;ressu.re Drop,,p. s. i 25 Hrs. Pressure Drop, p. s 0, Hrs. Pressure Drop, p. s. l Torque Breakdown, 80250 F Leakage,

Percent .l

The Low Temperature'lerque test of the foregoing table is essentially a measure of the resistance of the grease to congealing and of its ability to afiord proper lubrication under extremely low temperature conditions, such as are encountered in aircraft at very high altitudes. The apparatus employed for the test consists essentially of a vertically mounted hollow spindle with a No. 204K Conrad-type S-ball' bearing. mounted on the bottom, and a drum on which is wrapped a coiled line for applying being washed out of the bearing in the presence of water. Briefly, the" test involves the 204K Conrad ball bearing mentioned above packed with 4 grams of the grease and clamped in a tight fitting housing which allows the inner race to rotate. The latter is mounted on' a horizontal shaft and rotated at 600 R; P. M. while a line stream of distilled water is directed against the end plate of the bearing housing just above the outer opening of the bearingv housing. This operation is continued for one hour, and the loss 9. in weight of the dried bearing is then determined. This loss in weight divided by the weight of the grease used in packing the bearing is reported as the percentage loss.

The Norma-Hoffmanri Oxidation test is a measure of the resistance to oxidation of lubrieating greases when stored under static conditions for long periods of time, as when coated in thin films on anti-friction bearings, motor parts, etc. In this test five four-gram samples of the grease are put in flat sample dishes and placed in a stainless steel bomb sealed with a gasket in an atmosphere of oxygen under an initial pressure of 110 pounds per square inch at a temperature of 210 F. The pressure drop in pounds within the bomb is then recorded at different times up to 500 hours at shown in the table. A grease giving a pressure drop of less than 5 p. s. i. g. per hundred hours up to 400 hours in this test is generally considered to have excellent oxidation resistance properties.

The Torque Breakdown test is designed to evaluate the lubricating properties of greases used for the lubrication of anti-friction bearings. Two standard 3.9370 inch Timken tapered roller bearings packed with about 25 g. each of the grease under test, and a standard Federal Precision Ball Bearing No. 1211 packed with about 32 g. of the grease are employed, the packed bearings being weighed before test. In the test of each bearing, the bearing is assembled on a motor driven shaft supported by pillow blocks within a bearing housing mounted within an insulated chamber, with a system of levers connected to register any movement of the bearing housing in grams on a platform scale, whereby both the starting torque and the running torque can be measured. The insulated chamber is equipped with a copper coil tubing for the circulation of a cooling or heating medium, and

also with an insulated cover equipped with an electric heater and a motor driven fan, whereby the temperature of the chamber and bearing under test can be accurately controlled. In the tests reported in the table, which were conducted to determine per cent leakage of the test greases from the bearings, the temperature of each bearing was raised gradually from an initial 80 F. to 250 F. at the end of an hour and then maintained at this temperature for an additional two hours while the shaft was rotated at 1750 R. P. M. The bearing was then removed from the housing and weighed, and the weight of grease on the housing also determined. Grease leakage (grease escaping from both the bearing and housing) was obtained as the difference between these combined weights and the original weight of grease applied.

As shown by the foregoing Table I, very superior greases of the type suitable for use as ball and roller bearing lubricants are obtained based on calcium-sodium soaps of highly oxidized waxes according to our invention. The representative greases shown in the table are characterized by exceptional low temperature properties, water resistance and resistance to leakage from the bearings, as well as high dropping points and good working stability. Those inhibited with 1.9 per cent of phenylalphanaph thylamine show entirely satisfactory oxidation resistance. As shown by the table, in most of their properties they are markedly superior to a premium grade commercial ball and roller bearing grease.

Another series of greases was prepared em- 76 playing base oils of somewhat higher viscosities and of varying degrees of paraffinicity.

EXAMPLE 5 A grease was prepared from the following ingredients:

Pounds Wax oxidate 20.0 Lime 1.93 Caustic (dry basis) 2.05 Mineral oil 80.0 Water 6.0 Paratac (isobutylene polymer) 0.51

The oxidate was prepared by the oxidation of crude scale wax containing about 3 per cent of oil. The oxidation was carried out at 270 F. and 80 p. s. i. a. pressure, with an air rate of 20 cubic feet per hour per pound of charge. The oxidate obtained had a neutralization number of 181 and a saponification number of 287 and contained. 23.4 per cent of unsaponifiable matter.

The oil base comprised a blend of 70 per cent ofnaphthene base residual oil having an API gravity of 17.7 and a Saybolt Universal viscosity at 210 F. of 162.3 with 30 per cent of paraffin base distillate oil having an API gravity of 292 and a Saybolt Universal viscosity at F. of 102.6. The blend had an API gravity of 21.3" and a Saybolt Universal viscosity at 210 F. of 75.2.

'ri'fe amount of alkalies added was the theoretical amount to produce a soap of 50:50 calcium-sodium ratio. Paratac, which is a high molecular weight isobutylene polymer, was added to increase stringiness.

A dark green, slightly stringy grease was obtained having the following composition:

Per cent Total soap, calculated 16.8 Water, ASTM 0.3 Free fatty acid, ASTM 0.39 Paratac 0.5 Mineral oil 82.51

1 Includes 4.59 per cent unsaponifiable matter from wax oxidate.

EXAMPLE 6 A grease was prepared from the following ingredients:

Pounds Wax oxidate 40.0 Lime 4.83 Caustic (dry basis) 4.29 Mineral oil 108.34

1 Includes 3.64 lbs. water.

The oxidate was obtained by the oxidation of crude scale wax as in Example 5, followed by water washing, which was carried out by mixing the crude oxidate with water at about -170 F., employing 100 lbs. of water for 172.5 lbs. of crude oxidate, and thereafter permitting the water to settle out. This process was repeated twice, with an 83 per cent recovery by weight of oxidate. The water washed oxidate had a neutralization number of 202 and a saponification number of 305 and contained 12.0 per cent of unsaponifiable material.

The mineral oil was the same type as that employed in Example 5.

The amount of alkalies added was the theoretical amount to give a' soap having a calcininsodium ratio of 50:50, with a 10 per cent excess of lime.

ace-mos A grease was prepared from the following ingredients:

Pounds Wax oxidate 50.0 Lime a, 5.96, Caustic (dry basis) w .1 5.26 Mineral oil ,1. an, 66.3

1 Includes 3.1 lbs. water.

The oxidate was obtained by the oxidation of crude scale wax containing about 3 per cent of oil at 270 Fa, 80 p. s. i. a. pressure and an air rate of 30 cubic feet per hour per pound of charge. The oxidate obtained had a neutralization number of about 250 and a saponification number of I about 400, and contained about per cent of unsaponifiable matter. This crude oxidate was then water washed as in Example 6, giving a product which had a neutralization number of 202 and a saponification number of 295, and

which contained 13.0 per cent of unsaponifiables and 6.2 per cent of residual water.

The amount of a lkalies added was the theoreti amount to give a soap having a calcium-sodium ratio of 50:50, with all) percent excess of lime.

The oil base comprised a blend of "70 per cent of napththene base cylinder stock having an API gravity of 185 and a Saybolt Universal viscosity at 210 of 165 with per cent of parafiin base distillate oil having an API gravity of 291 and a Saybolt Universal viscosityat 100" F. of 102.6. The naphthene base cylinder stock was a residual oil obtained by redistilling a distillate fraction from a naphthene base crude.

The finished grease had the following composition:

Per cent Total soap, calculated 38.80 Water, ASTM 0.2 Free alkali, ASTM Neutral Mineral oil 1 61.00 Contains 2.6 per cent of unsaponifiable matter irom wax oxidatc.

EXAMPLE 3.

A grease was prepared from the following ingredients:

The oxidate was prepared by the oxidation of slack. wax containing about 23 per cent of oil at 270 F., 65 p. s. i. g. pressure and an air rate of cubic feet of air per hour per pound of charge. The oxidate had a neutralization number of 106 and a saponification number of 211, and contained 39.3 per cent of unsaponifiable material.

The mineral oil was a blend of 84 per cent naphthene base cylinder stock obtained as doscribed in Example '7 and having an API gravity of 172 and a Saybolt Universal viscosity at 210 F. of :8, with 16 per cent paraflinic distillate oil having an API gravity of 27.1 and a Saybolt Universal viscosity at 210 F. of 34.1. The blend had an API gravity of 18.8 and a- Saybolt Universal viscosity at 210 F. of 89.3.

The amount of alkalies added was the theoretical amount to give a soap having a calcium-sochum ratio of 18:82, with no excess of lime.

A smooth stringy grease was obtained having the following composition:

Pei cent Total soap, calculated 2.3.8 Water, ASTM 0.45 Free, alkali, as Ca(OH) 2, ASTM 0.69 Mineral oil -1,- 1 75.06

3 Infceluding 13.6 per cen-t-unsaponifiablc mattcrfrom-wax EXAMPLE 9 A grease was prepared from the following in gredients:

Pounds Wax oxidate 25.0 Lime 1 1.96 Caustic (dry basis) m.,, 1.73 Mineral oil 1., 61.0 Water (as aid in saponification) 3.0

The oxidate was prepared by the oxidation of slack wax from awax distillate containing about 20 per cent or oil. The oxidation was carried out at a temperature of 250 F., 65 p. s. i. g. pressure and an air rate of 30 cubic feet of air per pound of charge. The oxidate had a. neutralization number of 109 and a saponification number of 194 and contained 26.4 per cent of unsaponifiable material.

The mineral oil was of the same type as that used in Example 8.

The amount of alkalies added was the theoretical amount to give a soap having a calcium-sm dium ratio of 50:50 with a 10 per cent excess of lime.

A smooth green grease of stringy texture was obtained having the following composition:

Per cent Total soap, calculated 23.2 Water, ASTM 0.2 Free alkali, as Ca(OI-I)z, ASTM 0.01

Mineral oil 76.59

flntcludes'ij per cent unsaponifiablo matter from wax oxida EXAMPLE 10 A grease wasprepared from the follcwinginredients:

The oxidate was prepared by the oxidation of crude scale wax containing about 3 per cent of oil at 270 F., 80 p. s. i. a. pressure and an air rate of 30 cubic feet of air per hour per pound of charge. The oxidate had a neutralization number of 251 and a saponification number of 400 and contained 10.1 per cent of unsaponifiable material.

The mineral oil was a naphthene base distillate oil having an API gravity of and Saybolt Universal viscosity at 210 F. of 89.3 seconds.

The amount of allralies employed wasthe theoretical amount to give a soap having a'calciumsodium ratio of 15 :55, with no. excess of alkali.

The finished grease had the following composition:

'Per cent Total soap, calculated 29.5 Water, ASTM 0.4 Free alkaii, as Ca(OH) 2, ASTM 0.22 Mineral oil 1 69.88

1 Includes 2.82 per cent unsaponifiable matter from wax oxidate.

a chassis lubricant.

1 TABLE II Chassis and wheel bearing greases Grease N t 6 s 9 10 11 B Oxidatc: I

Neutralization No 181 202 202 106 100 128.

Sap0nificatio11No 287 295 211 194 200 Treatment Nona... WaterWashed. None. None.... Acid Treated. CazNa Ratio 50250.- 50150 :55 CHEM: Mixed..- Naphthenic,

Gravity, API 21.3. 13

Vista, SUS. 210 F Penetration at 77 F., ASTM'.

Unworkcd Worked Strokes Worked 5,000 Strokes Worked 100,000 Strokes. Penetration at:

0 R, Unworked Dropping Point, F., Low Temp. Torque 2,000 g. cm.:

Sec/Rev. it-- EXAMPLE 11 A grease was prepared from the following ingredients:

The oxidate was prepared by the oxidation of a slack wax containing about 23 per cent of oil at 270 F., p. s. i. a. pressure and an air rate of 20 cubic feet of air per hour per pound or charge. The crude oxidate had a neutralization number of and a saponification number of 258 and contained 23.3 per cent of unsaponifiable material. This crude oxidate was treated by heating to F. with 20 per cent by weight of a 40 per cent solution of sulfuric acid. After removal of the acid layer, the oxidate was washed. with water until free of mineral acid. The product thus obtained had a neutralization number of 128 and a saponification number of 200.

The mineral oil was the same as that employed in Example 10.

The amount of alkalies employed was the theoretical amount to give a soap having a calcium-sodium ratio of 45:55, with no excess of alkali.

The finished grease had the following composition:

Per cent Total soap, calculated 17.42 Water, ASTM Trace Free fatty acid, ASTM 0.08 Mineral oil 1 82.50

Includes 5.78 per cent unsaponifiable matter from wax oxidate.

As shown in the tables, the greases of our invention have superior properties at both high and low temperatures as compared with commercial greases in addition to greatly improved water resistance and anti-leal-zage properties as indicated by the Torque Breakdown test.

Grease #6 was successfully prepared in a 4000 pound plant batch and this was tested as a chassis lubricant for the lubrication of plant service equipment and in road tests in competition with commercial lubricants. More than 100 vehicles in refinery service including passenger cars, trucks, tractors and road graders, were lubricated for more than 300,000 miles of operation during a one-year period under a wide variety of service conditions including severe wet weather conditions. This grease not only gave excellent lubrication but also provided. adequate protection against rusting and corrosion, and no failures occurred in any of the tests during this period attributable to faulty lubrication. Consumption was normal and pumpability in conventional equipment was satisfactory during the entire period. In comparison with a commercial grease of good grade, the test grease was shown to have definitely improved water resistance while all other respects it was at least equivalent. This grease was also tested in a 20,000 mile high speed road test, employing new 1949 automobiles of Chevrolet, Ford, Plymouth and Cadillac make. The chassis were lubricated at the start of the test and every 1000 miles thereafter. Good lubrication was maintained throughout the test in every case, with no difficulties of any kind arising due to the lubricant.

Grease #7 was tested as a wheel-bearing lubricant in three of the cars in the 20,000-mile test described above. At the beginning of the test,

assume each :front wheel assembly of these cars was cleaned thoroughly and lubricated with the test grease, employing 6-10 grams in the bearings according to bearing size and 75-80 grams in the hub. At the end of the test, lubrication was judged to be from good to excellent in every case except for one wheel where a mechanical defect was found to exist. The balls were bright and oily with no oil leakage or only slight leakage. Two commercial lubricants employed in this test gave generally good lubrication, but considerable leakage occurred in most cases and discoloration of the balls was found in several cases at the end of the test.

Grease #9 was employed as an automotive wheel-bearing lubricant in another road test in competition with a commercial wheel-bearing grease of recognized good grade prepared from stearic acid and inhibited with 0.5 per cent by weight of diphenylamine. Two new 194.8 Chevrolet sedans were employed. in this test, one being lubricated with grease #9 and the other with the commercial grease. At the beginning of the test. each front wheel assembly of the cars was cleaned lubricated with grams of grease, the bearing cages being packed 100 per cent full with about 10 grains of grease on the inner bearings and 6 grams on the outer bearings; the remainder of the 90 gram charge of grease was placed in the hub. The cars were operated at speeds between 10 and 75 miles per hour for atotal distance of about 27,000 miles each. At the end of the test, all of the bearings lubricated with grease werebright and oily, with good coverage of the races and balls and with very little alteration in the grease, whereas the commercial grease hardened considerably and some staining and rusting of the balls and races occurred in the bearings lubricated with this grease. No apreciable leakage occurred with either grease.

In the car lubricated with grease #9, 7.8 grams of grease remained on the inner bearings and grams on the outer bearings, as compared with 7 grams and grams, respectively, for the lubricate. with the commercial grease.

Obviously, many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore only-such limitations should be imposed as are indicated in the appended claims.

We claim:

1. A. lubricating grease comprising essentiall a mineral oil fraction of lubricating characterisas the predominating constituent, and about 10-40% by weight of a mixed calciuinsodluin scan of a saponiiiable wax oxidate obtained ox a petroleum wax undercontrolied conditions to due-e an oxidation product having a neutralization number in the range of from about 100 to about 300 and a saponification numher in the range of from about 1.75 to about 450,

16 said grease having adropping point of at least 482 F., the proportion of sodium soap in said mixed calcium-sodium soap being at least by weight.

2. Claim 1 wherein the Wax oxidate has a ratio of neutralization number to saponification number of at least 0.5.

3. Claim. 1 wherein the Wax oxidate is extracted with water before saponification to form the mixed calcium-sodium soap.

4. Claim .1 wherein the wax oxidate is extracted with a mineral acid before saponification to form the mixed calcium-sodium soap.

5. Claim 1 wherein the ratio of calcium to sodium soap is within the range from about 25:75 to about 60:40,.

8. Claim 1 wherein the ratio of calcium to sodium soap is within the range from about 40:60 to about 60:40.

'7. Claim 1 wherein the mineral oil fraction is a. blend of a naphthene base cylinder stock with a paraffin base distillate.

8. A lubricating grease comprising essentially about 10 to 40 per cent by weight of about a :50 calcium-sodium soap of a wax oxidate obtained by oxidizing a petroleum wax under controlled conditions to produce an oxidation product having neutralization number in the range of from about 100 to about 125 and a saponification number in the range from about 175 to about 225, and about 90 to per cent by weight of a mineral lubricating oil having a Saybolt Universal viscosity at 210 F. of about 50 to 120 seconds, said oil being a blend of a. major proportion of a naphthene base cylinder stock and a minor proportion of paraifin base distillate oil.

,9. A lubricating grease comprising essentially about 15 to 40 per cent by weight of about a 50:50 calcium-sodium soap of water-washed wax oxidate obtained by oxidizing a petroleum wax under controlled conditions to produce oxidation roduct having a neutralization number in the range from about 175 to about 275 and a saponification number in the range from about 250 to 450, and about to 60 per cent by weight of a mineral lubricating oil having a Saybolt Universal visccsity at 210 F. of about 60 to seconds, said oil being a blend of a major proportion of a naphthene base cylinder stock and a minor proportion of paraffin base distillate oil.

JOHN K. MCKINLEY. BEN A. SCOTT. WILLIAM H. GOFF. ROY F. NELSON.

References Cited in the file of this patent UNITED STATES PATENTS Number 

1. A LUBRICATING GREASE COMPRISING ESSENTIALLY A MINERAL OIL FRACTION OF LUBRICATING CHARACTERISTICS AS THE PREDOMINATING CONSTITUENT, AND ABOUT 10-40% BY WEIGHT OF A MIXED CALCIUM-SODIUM SOAP OF A SAPONIFIABLE WAX OXIDATE OBTAINED BY OXIDIZING A PETROLEUM WAX UNDER CONTROLLED CONDITIONS TO PRODUCE AN OXIDATION PRODUCT HAVING A NEUTRALIZATION NUMBER IN THE RANGE OF FROM ABOUT 100 TO ABOUT 300 AND A SAPONIFICATION NUMBER IN THE RANGE OF FROM ABOUT 175 TO ABOUT 450, SAID GREASE HAVING A DROPPING POINT OF AT LEAST 482* F., THE PROPORTION OF SODIUM SOAP IN SAID MIXED CALCIUM-SODIUM SOAP BEING AT LEAST 40% BY WEIGHT. 